Use public pull diagnostics for F#

[kayle]

F# hosts an independent language server in Visual Studio rather than using Roslyn's diagnostic handlers. The Visual Studio client prerequisite for public LSP pull diagnostics is already available, so this migrates the F# server to textDocument/diagnostic without a dual private/public period.

This removes only the private F# document diagnostic capability and _vs request handler. The independent project-context provider remains registered. Public diagnostic capabilities use the Visual Studio-compatible syntax identifier, advertise inter-file dependencies, and intentionally do not advertise workspace diagnostics because F# does not implement a workspace diagnostic endpoint.

Document pulls now return full or unchanged public reports using stable project-snapshot result IDs.

[github-actions]

❗ Release notes required

You can open this PR in browser to add release notes: open in github.dev

@kayle,

Caution

No release notes found for the changed paths (see table below).

Please make sure to add an entry with an informative description of the change as well as link to this pull request, issue and language suggestion if applicable. Release notes for this repository are based on Keep A Changelog format.

The following format is recommended for this repository:

`* . (PR #XXXXX)`

See examples in the files, listed in the table below or in th full documentation at https://fsharp.github.io/fsharp-compiler-docs/release-notes/About.html.

If you believe that release notes are not necessary for this PR, please add NO_RELEASE_NOTES label to the pull request.

Change path	Release notes path	Description
`src/Compiler`	docs/release-notes/.FSharp.Compiler.Service/11.0.100.md	No release notes found or release notes format is not correct